Field of the Invention
This invention relates to combustion of hydrocarbon fuel within the combustion zone of an internal combustion engine and, in particular, to the placement of a catalyst within the combustion zone for cracking the hydrocarbon fuel molecules and thus producing a more volatile hydrocarbon fuel.
A method of catalytically supporting thermal combustion is disclosed in U.S. Pat. No. 3,870,455, issued Mar. 11, 1975, in which catalytically-active materials including a platinum group metal is deposited on a catalytic slip or composite which contains a mixture of alumina, a rare earth metal oxide, and a metallic oxide wherein the metal is IVB, selected VIB metals, and mixtures thereof. Provision is made for contacting hydrocarbon fuels mixed with a portion of air with the catalyst to form an effluent of high thermal energy. The catalysts are particularly useful in promoting the oxidation of materials frequently present in exhaust gases from the combustion of carbonaceous fuels. While this prior patent is an attempt to catalytically improve thermal combustion by contacting the hydrocarbon fuel with the catalyst, the patent does not specifically disclose an efficient means by which the catalyst can be incorporated within the combustion zone of an internal combustion engine, and particularly an internal combustion engine which is placed on board a motor vehicle. Further, the catalysts disclosed in this patent are for promoting the oxidation of the hydrocarbon fuel molecules and are quite different from the use of the acidic catalysts of the present invention which are used primarily for the purpose of cracking hydrocarbon fuel molecules by breaking the carbon-to-carbon bonds thereof, allowing more efficient oxidation of the lighter fuel molecules which are produced. Furthermore, the present invention provides a means by which the catalysts can be incorporated within the combustion zone of the internal combustion engine without the requirement of changes in the structure of the engine.